1. Field of the Invention
The present invention relates generally to display systems, and more particularly to projection display systems.
2. Description of the Background Art
A two-dimensional projection image may be formed by using one or more linear arrays of light-modulating pixels. The light-modulating pixels may comprise, for example, GRATING LIGHT VALVE (GLV) pixels. Publications describing GLV devices and their application to display systems include: “Grating Light Valve Technology: Update and Novel Applications,” by D. T. Amm and R. W. Corrigan of Silicon Light Machines in Sunnyvale, Calif., a paper presented at the Society for Information Display Symposium, May 19, 1998, Anaheim, Calif.; “Optical Performance of the Grating Light Valve Technology,” David T. Amm and Robert W. Corrigan of Silicon Light Machines, a paper presented at Photonics West-Electronics Imaging, 1999; “An Alternative Architecture for High Performance Display,” R. W. Corrigan, B. R. Lang, D. A. LeHoty, and P. A. Alioshin of Silicon Light Machines, a paper presented at the 141st SMPTE Technical Conference and Exhibition, Nov. 20, 1999, New York, N.Y.; and U.S. Pat. No. 6,215,579, entitled “Method and Apparatus for Modulating an Incident Light Beam for Forming a Two-Dimensional Image,” and assigned at issuance to Silicon Light Machines. The above-mentioned publications are hereby incorporated by reference in their entirety.
In such display systems, the linear array modulates an incident light beam to display pixels along a column (or, alternatively, a row) of the two-dimensional (2D) image. A scanning system is used to move the column across the screen such that each light-modulating pixel is able to generate a row of the 2D image. In this way, the entire 2D image is displayed.
There are challenges, however, in implementing a scanning system that efficiently renders a high quality video image. For example, one measure of the efficiency of the scanning system is its duty cycle. The duty cycle indicates the fraction of time during which the image is being actively rendered on-screen and the fraction of time during which no image is being actively rendered. The higher the duty cycle is; the higher the efficiency is. Hence, achieving a high duty cycle is one challenge.
As another example, the quality of the video image depends on a number of factors. One factor is the refresh rate. The refresh rate is the rate at which an image is displayed upon the screen. Low refresh rates result in a video image that appears to “flicker” to a viewer. Sufficiently high refresh rates are desirable to reduce or eliminate flicker in the video image, and achieving a high refresh rate is another challenge.